Koi Health

Koi Health
By Alan Stein, KHA

Summer’s here and that means growing season.  This is the prime time to feed often for maximum growth.  It is also time to watch your water quality.

To grow large Koi we feed high protein food often to provide the amino acids needed for growth.  The Koi produce ammonia which is detrimental to health, and pheromones which limit growth.

Pheromones are the chemical signals that tell Koi in overcrowded conditions to stop growing.  Pheromones and chemical pollutants are best controlled by regular water changes.

A 10-15% weekly water change is much less stressful to your Koi than a 50% monthly change.

Some people automate their water changes using drip irrigation nozzles designed for gardening to constantly add a small amount of fresh water to their pond, allowing the overflow drain to get rid of the excess.

Water changes below 15% generally do not need to be dechlorinated.

Let’s talk a little about ammonia.

Ammonia is the primary waste product of protein metabolism and is part of the nitrogen cycle.  The nitrogen cycle is the energy source for life on earth.

Here’s how it works:
1)    Protein is broken down into amino acids that are used for growth and energy.  The waste product is ammonia.
2)    The ammonia is broken down by bacteria into nitrite providing energy for the bacteria.
3)    The nitrite is broken down by other bacteria into nitrate providing energy for these bacteria.
4)    The nitrate is utilized by plants (and algae) for growth and is released as nitrogen into the environment.

The cycle operates the same on human waste in a sewage treatment plant, horse manure in your garden, or Koi waste in your pond.

So, why worry about a little ammonia in your pond?

In the wild, one fish may have millions of gallons of fresh water to dilute its waste.

Not so in your pond.  Think of it this way, the waste from a pack of dogs roaming a 10 square mile area will have little effect.  The waste of the same pack of dogs confined to your bedroom will become toxic very quickly.

High concentrations of ammonia will destroy gill tissue, just as breathing ammonia will destroy your lungs.  High concentrations of nitrite will block the Koi’s ability to transport vital oxygen in its blood, similar to carbon monoxide poisoning in mammals.

That’s the simple version.

There are other factors involved including pH, oxygen saturation, fish load and water temperature.  I will discuss these in a future article.

The ammonia and nitrite in your pond is treated by your “filter”, essentially a small sewage treatment plant more properly called a bio-converter.

It houses the bacteria that convert ammonia to nitrite to relatively harmless nitrate.

Don’t wait for you fish to die to determine if your bio-converter is functioning adequately.  Buy a nitrite and an ammonia test kit and test your water.

There are two types of ammonia test kits.  Some dechlorinators such as Amquel or Ultimate can affect the test, so talk with your dealer about selecting the right test kit.  Also remember to replace your kit yearly, an outdated kit will give you false negative results.

While you are at your dealer, buy a copy of “Koi Health and Disease” by Eric L. Johnson D.V.M.  This is a must.  It is the definitive owners manual on Koi.

OK, that’s enough chemistry for now.  Go sit by your pond, feed the fish and enjoy an iced tea.

Here’s some future topics:
1)    What is pH, and why should I care?
2)    Parasites and other icky things growing on your koi.
3)    Poop eating bacteria and holes in your fish.
4)    Why little box filters do little good.
5)    Why can’t I put a half dozen jumbo Koi in my 500 gallon water garden?
6)    Your friend, the microscope.  It’s not just for kids anymore.

Which topic would you like next?  Any suggestions for other topics?  Please let us know!